Mineral oil stocks are the prime source of lubricants for an almost endless list of applications. Nearly all of the lubricants are formulated with a variety of additives. Lubricant additives generally are defined simply as materials which enhance or impart desirable properties to a mineral-base oil. The high quality of modern lubricants results for the most part from the use of additives.
Lubricating oils and related hydraulic and transmission fluids for present day machinery, and particularly for present day internal-combustion engines and other uses contain a wide variety of additives. The additives usually are classified according to their intended function such as dispersant; oxidation, corrosion and rust inhibitor; viscosity-index (VI) improver; pour-point depressant; and antiwear agents, antifoam agents; and the like.
The advent of high speed automotive engines in particular, coupled with increased engine operating temperatures and increased complexity of antipollution devices associated with such engines, has resulted in substantial increases in additive quantities in automotive lubricating oils to meet a continuing demand for improved properties and results. The quantities of additives employed in some uses have been approaching quantities so large as to affect negatively the primary mission of the lubricating oil: to lubricate. Needed is a single additive which will provide a multiple function to satisfy at least some of the basic requirements of individual additives for lubricating and other oils now presently satisfied by a package of several additives. With such an additive, the quantity of overall additives employed in the lubricating oil potentially could be substantially reduced, permitting a single effective unit quantity to fulfill multiple requirements.